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Supersonic Flight: How Fast Will We Go?

In my previous blog I wrote about an airplane design with a blended wing body with engines that can operate on different fuel types. In this blog I’d like to tell you about another interesting area of research and what might be the future of traveling by plane: supersonic and hypersonic flight.

What is the difference between supersonic flight and hypersonic flight?

Supersonic flight is a flight that takes place with a speed faster than the speed of sound. This is also called Mach 1.

How fast is this?

The temperature of the atmosphere and the altitude affects the speed of sound. That’s why we use a certain temperature and altitude to define the speed of sound. At 20 degrees Celsius and at sea level the speed of sound is 343,2 meters per second which is 1,236 kilometers per hour.

Hypersonic flight is defined as flights that take place at Mach 5 and above; 5 and more times the speed of sound!

This concept of an aircraft that could fly at supersonic speeds over land is being used by researchers, especially at NASA’s Langley Research Center, to continue to test ideas on ways to reduce the level of sonic booms. Its technologies – the F-100-like propulsionsystem, a tail blister, and the overall shape – are combined to achieve a lower target perceived decibel level. Image credit: NASA

Subsonic flight

Current commercial aircraft fly with a cruise speed depending on the model and make of the aircraft that ranges between Mach 0.81 through Mach 0.86, that is a speed in the range of 900 km per hour. We call this subsonic flight. Concorde flew with a cruise speed of about 2,100 km per hour. The future generations of very fast commercial aircraft will fly with speeds of 4-5 times the speed of sound, that is in the range of 4,000-5,000 km per hour.

History of supersonic flight

Development of supersonic flight started already in the early fifties of the 20th century, initially mainly driven by military developments. A lot of research was done with the development and research to manned space flight. A famous rocket type aircraft that still holds the world record is the X-15, which achieved a speed of Mach 6.72 or 7,274 kilometers per hour.

NASA Dryden’s F-15B Research Tes. Image credit: NASA / Tom Tschida

The famous Concorde

Commercial aircraft able to fly faster than the speed of sound were developed in the nineteen sixties. The Concorde was the most famous one; a joint design by France and Great Britain. This aircraft was operated between 1976 and 2003.

Image credit: Ger Buskermolen

New developments

Although there were just a limited number of supersonic commercial aircraft sold, there is still a lot of research going on to travel with speeds that will enable reaching far away destinations at the globe within just a few hours. Remember, Concorde flew at a speed of 2,100 km per hour, with newer generations high speed air travel will more then double that speed, enabling Amsterdam New York in just less then two hours!

A possible roadmap to commercial hypersonic flights is first to develop commercially viable supersonic type of aircraft that operate in earth’s atmosphere as we are doing right now with commercial aviation.

Outer space

A next development might be the evolution into a combination of atmospheric and non-atmospheric flights; by this the flight follows a trajectory partly in the atmosphere and partly in outer space. The goal is to achieve higher speeds with more efficient operation.

These type of aircraft will take off like a current type aircraft from a runway at an airport but will climb through outer space and then at the destination will re-entry the atmosphere again and land like a conventional aircraft.

Cockpit of a Concorde

KLM is participating in the development of this type of air transport. We are a partner in the XCOR Space project: a project developing commercial space flight one of the operation sites will be Curacao. In this concept a 40 minute flight into space will be made possible taking off and landing in a space plane from a conventional runway.

High speed commercial aircraft

Several design studies to next generation high speed commercial aircraft are ongoing. One step is to develop a commercial supersonic business jet flying at mach 1.5. Airbus recently patented a design that will fly 4.5 times the speed of sound, enabling flying Amsterdam-New York in just an hour!

There are enormous technical challenges to overcome, and it will take several decades before we will see supersonic or hypersonic aircraft in commercial aviation. But the desire to reach any major destination on earth in just a fraction of the current travel time, still triggers scientists and engineers from all over the world. Isn’t that amazing?

Concorde facts

Concorde was jointly developed and produced by British and French engineers.

Concorde flew with a cruise speed of about 2,100 km per hour, twice the speed of sound.

The Concorde was operated between 1976 and 2003.

A total of 20 aircraft were built. Six prototypes and 14 aircraft were devided between Air France and British Airways.

The extra power of the Rolls Royce engines was realized through the exhaust and reheat system.

In july 2000 a tragic accident happened minutes after take off from Paris. 113 people were killed and all Concorde aircraft were grounded for more than a year.

The Concorde flew its fastest transatlantic flight on February 7, when it traveled from New York to London in 2h and 52m.

Jan Bos

4 years ago

Hello Rob,
Nice future vision. I understood that there are even plans to get the Concorde up and running again.
However, speedy flying is one, what about an even more revolutionary idea, “suborbital flights”. A bit higher up, but with a huge potential in getting there fast.
Lets see what the future brings.
Regards, Jan

Rob Duivis

4 years ago

Dear Jan,
Yes, suborbital flights are also considered in various designs, the aircraft needs to be powered by a combination of engines that can operate in the ambient atmpsphere as well as in non ambient conditions.
Again very challenging!

Arne R.

4 years ago

How fast do you NORMALY cruise at? I remember once, above Burma-Thailand area, there was atleast 4 captains on board. They even told us on the caling. And onboard flight map and speed and so on I remeber to se above 1100Kmh.. strangest route for an longhaul Ams-Mnl? Could be good wind conditions up there? Anyway, 4-5 years ago, will never forget :-)

Rob Duivis

4 years ago

Dear Anne,
Cruising speed with nowadays aircrafts is in the range of 900 klm per hours, it is known phenomenon that at high tailwinds caused by jetstreams over the Atlantic for example the speed of an aircraft relative the ground (groundspeed) can go up well over 1000 km per hours.
But that’s still far away from flying at super or hypersonic conditions.

Bob Straub

4 years ago

Sometimes, if you’re lucky, you can see direct evidence of your near-sonic speed from a window seat near the wing. I was on a B-727 flying from New York to Chicago many years ago, and observed unusual vertical lines above the wing. The pilot told me that they were standing waves caused by abrupt changes in air density as air flowed over the top of the wing at high speed. Here’s a video of someone else’s observation:

Daniel Klaas

4 years ago

At my budget, flying at sub-sonic speeds is usually unaffordable. How will the airline manufacturers reduce the fuel consumption, acquisition cost, and maintenance of super-sonic and hyper-sonic aircraft? For now, they need to concentrate on reducing the cost of sub-sonic flight further. (what the A380, 747-8, and 787 are trying to achieve) What about the environmental factors of such high speed aircraft? A good compromise could be flying in the near sonic regions, trans-sonic flight, or a commercial version of the super-cruising F-22. Is there any indications of commercial development in the last two areas?

Rob Duivis

4 years ago

Dear Daniel,
Good questions, yes, environmental aspects are indeed a very important issue; noise, emission levels, fuelconsumption and the impact on the atmosphere and environment.
That’s for example the reason that in the study of the AHEAD aircraft (see my previous blog) a group of climate scientists participated and studied the impact of the aircraft on the climate and cloudformation.
Next generation of high speed and very high speed aircraft regardless if that will be trans-sonic, supersonic or hyper-sonic designs need to take into account all the aspects mentioned above.

John Doo

Dr. Ghayur

2 years ago

i
hello
i am Dr Ghayur.
i want to propose a design to commercial airlines jets manufacturers with high speed as high as 3500 kms per hour.
i suggest planes with two engines take off and then the system that give a plan high speed may start operating at studies and researches made height.
i mean we may take from Dubai to JFK NEW York in about two hours.
now we need to model the aeroplane body for such a high speed.
if i am given opportunity with confidence not be cheated i can propose.